Scientists Accidentally Created A Hybrid Offspring From Two Endangered Fish

Researchers are working with two types of endangered fish species to try and see if they could be bred in captivity to prevent them from going extinct. The two fish are the American paddlefish and Russian sturgeon. The Russian sturgeon is the fish used to make high-end caviar, and the fish itself is a carnivore that eats crustaceans and small fish off the floor of rivers, lakes, and coastal areas.

The American paddlefish is founded 22 states in the US and is a filter feeder that strains zooplankton from the water. Its name comes from the long snout that's covered with sensory receptors. Scientists didn't believe that sturgeon and paddlefish could interbreed, but when sperm from the paddlefish and eggs from the Russian sturgeon were combined, a hybrid species was born.

Hungarian researchers created the accidental hybrid, and the resulting offspring have been nicknamed Sturddlefish. The hybrid fish was accidentally created last year while the researchers were trying to induce gynogenesis in Russian sturgeon, which is a form of asexual production that requires the presence of sperm but not the contribution of DNA.

The team was shocked when the paddlefish sperm they were using successfully fertilized the sturgeon eggs. The researchers say hybridization was completely unintentional, and hundreds of hybrids emerged from the eggs. About a month later, more than two-thirds of the hybrids were still alive. About 100 of the hybrid fish are alive today.

Scientists had assumed that the fish were too evolutionarily diverged to be hybridized, but they were wrong. The hybrid fish created exhibit traits from both species. All have their mother's mouth and carnivorous appetite, but some have the fins and snout from the father, but those aspects are slightly smaller. The scientists say that while some fish have nearly equal amounts of maternal and paternal DNA and look like a perfect mix of both species, some have a double dose of DNA from the mother and look more like sturgeon than paddlefish.